HVAC BLOWER

2000 Ford Excursion

2000 Excursion, 6.8L V-10, 47,000 mi, front and rear A/C. Front fan motor started making noise, obvious bearing failing. Started vehicle with A/C controls in on position, fan at medium speed, made noise and fan quit but still would work (although noisily) in Hi position. Changed blower motor, works quietly now but still in only Hi speed; will not work at slower speed settings. What is next? Replace switch? Is there a resistor built into the fan switch? Do you remove the radio to get to the switch? Thanks, Doug, Arkansas.